The CSP can be a cash back card, you can always cash out the points for 1 cent each. It is not the best value, but it is available. This means if you just do the sign up bonus you'll get $590 after spending $4k and adding an authorized user, or 14.75% back on your spending.
I open up new cards to hit sign up bonuses for our daycare spending. Bank of America Premium card will get you $500 after spending $3k (but has $95 fee), plus reimburse you for getting TSA pre-check or Global Entry, and reimburse $100 per calendar year in airline fees (you can buy a $100 American Airlines gift card for free). Ignoring the Global Entry, I should end up getting $620 for spending $3,000, or 20.6% back on both of those cards (his and hers).
If you have an actual business, go for the Chase Ink Preferred before the CSP. You'll get 80,000 points after spending $5k in 3 months.